1. Field of the Invention
The present invention relates to a medical needle device having a winged shield for the prevention of needle-stick injuries, in which a cannula can be stored safely after use.
2. Related Background Art
Conventionally, contamination and infection due to needle-stick injuries from injection needles, puncture needles and the like have been a problem in medical facilities. In particular, recently, as hepatitis B, hepatitis C, HIV (human immunodeficiency virus) and the like have become a widespread social issue, there is a demand for systems that actively prevent the occurrence of accidents such as needle-stick injuries and the like.
As a way to prevent needle-stick injuries, various injection needle devices that have a configuration in which a cannula is covered by a cover when injection needles or puncture needles are collected after use have been proposed. In most cases, such a system for preventing needle-stick injuries has a cylindrical protection cover (hereinafter, referred to as a shield) for preventing needle-stick injuries after use, and the shield can slide with respect to an injection needle. That is, the system is configured so that the injection needle can be either exposed or covered by the shield depending on the sliding state of the shield.
Meanwhile, for measures such as an infusion, a blood transfusion, extracorporeal blood circulation and the like, winged injection needle devices are used widely. Winged injection needle devices have a structure in which wings are mounted to a hub that has a front end at which an injection needle is fastened and a rear end that is connected to an infusion tube. Thus, a system for preventing needle-stick injuries for a winged injection needle device necessitates a special structure. That is, the structure has to be such that the wings do not obstruct the sliding of a shield. Conventional structures for achieving this are categorized into a type in which wings are attached to a cannula or a hub and a type in which wings are attached to a shield.
Examples of the latter structure are described in, for example, JP H06(1994)-7861B, International Publication No. WO 91/04761, or U.S. Pat. No. 5,088,982. In each of these conventional examples, wings are attached to the outer peripheral surface of a slidable cylindrical shield, and the wings slide together with the shield on the outer side of an injection needle. In order to prevent needle-stick injuries after use of the injection needle, the shield is slid so that the tip of the injection needle can be covered.
During a puncturing action using the above-mentioned injection needle device in which the wings are attached to the shield, the shield is held by hand. Therefore, it is required that the injection needle device be provided with a mechanism in which a hub can be held securely with the shield and is integrated with the shield. Furthermore, after the injection needle after use is retracted into the shield so that the tip of a cannula is covered by the shield (after needle storage), it is required that the cannula that has been retracted be held securely in the shield and that this state be maintained securely. On the contrary, during a storing action for retracting the injection needle after use into the shield, a force for holding the hub with respect to the shield rather should be weak.
As described above, it is preferable that the respective holding forces for holding an injection needle with a shield during a puncturing action, during a storing action, and after needle storage be set suitably.
However, in conventional injection needle devices with a winged shield, a common mechanism is used to hold an injection needle during a puncturing action, during a storing action, and after needle storage, and thus the respective holding forces used during the puncturing action, the storing action, and after the needle storage cannot be attained suitably, which has been disadvantageous.